java.lang.Object
- org.apache.commons.codec.binary.BaseNCodec

All Implemented Interfaces:

BinaryDecoder, BinaryEncoder, Decoder, Encoder

Direct Known Subclasses:

Base16, Base32, Base64
```
public abstract class BaseNCodec
extends java.lang.Object
implements BinaryEncoder, BinaryDecoder
```
Abstract superclass for Base-N encoders and decoders.
This class is thread-safe.

You can set the decoding behavior when the input bytes contain leftover trailing bits that cannot be created by a valid encoding. These can be bits that are unused from the final character or entire characters. The default mode is lenient decoding.
- Lenient: Any trailing bits are composed into 8-bit bytes where possible. The remainder are discarded.
- Strict: The decoding will raise an IllegalArgumentException if trailing bits are not part of a valid encoding. Any unused bits from the final character must be zero. Impossible counts of entire final characters are not allowed.
When strict decoding is enabled it is expected that the decoded bytes will be re-encoded to a byte array that matches the original, i.e. no changes occur on the final character. This requires that the input bytes use the same padding and alphabet as the encoder.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class BaseNCodec.AbstractBuilder<T,B extends BaseNCodec.AbstractBuilder<T,B>>
Builds Base64 instances.

Field Summary

Fields
Modifier and Type	Field	Description
`protected static CodecPolicy`	`DECODING_POLICY_DEFAULT`	The default decoding policy.
`protected int`	`lineLength`	Chunksize for encoding.
`protected static int`	`MASK_8BITS`	Mask used to extract 8 bits, used in decoding bytes
`static int`	`MIME_CHUNK_SIZE`	MIME chunk size per RFC 2045 section 6.8.
`protected byte`	`pad`	Pad byte.
`protected byte`	`PAD`	Deprecated. Use `pad`.
`protected static byte`	`PAD_DEFAULT`	Byte used to pad output.
`static int`	`PEM_CHUNK_SIZE`	PEM chunk size per RFC 1421 section 4.3.2.4.

Constructor Summary

Constructors
Modifier	Constructor	Description
`protected`	`BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength)`	Deprecated. Use `BaseNCodec(AbstractBuilder)`.
`protected`	`BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength, byte pad)`	Deprecated. Use `BaseNCodec(AbstractBuilder)`.
`protected`	`BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength, byte pad, CodecPolicy decodingPolicy)`	Deprecated. Use `BaseNCodec(AbstractBuilder)`.
`protected`	`BaseNCodec(BaseNCodec.AbstractBuilder<?,?> builder)`	Constructs a new instance for a subclass.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`protected boolean`	`containsAlphabetOrPad(byte[] arrayOctet)`	Tests a given byte array to see if it contains any characters within the alphabet or PAD.
`byte[]`	`decode(byte[] array)`	Decodes a byte[] containing characters in the Base-N alphabet.
`java.lang.Object`	`decode(java.lang.Object obj)`	Decodes an Object using the Base-N algorithm.
`byte[]`	`decode(java.lang.String array)`	Decodes a String containing characters in the Base-N alphabet.
`byte[]`	`encode(byte[] array)`	Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
`byte[]`	`encode(byte[] array, int offset, int length)`	Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
`java.lang.Object`	`encode(java.lang.Object obj)`	Encodes an Object using the Base-N algorithm.
`java.lang.String`	`encodeAsString(byte[] array)`	Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
`java.lang.String`	`encodeToString(byte[] array)`	Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet.
`protected byte[]`	`ensureBufferSize(int size, org.apache.commons.codec.binary.BaseNCodec.Context context)`	Ensures that the buffer has room for `size` bytes
`static byte[]`	`getChunkSeparator()`	Gets a copy of the chunk separator per RFC 2045 section 2.1.
`CodecPolicy`	`getCodecPolicy()`	Gets the decoding behavior policy.
`protected int`	`getDefaultBufferSize()`	Gets the default buffer size.
`long`	`getEncodedLength(byte[] array)`	Gets the amount of space needed to encode the supplied array.
`protected abstract boolean`	`isInAlphabet(byte value)`	Tests whether or not the `octet` is in the current alphabet.
`boolean`	`isInAlphabet(byte[] arrayOctet, boolean allowWSPad)`	Tests a given byte array to see if it contains only valid characters within the alphabet.
`boolean`	`isInAlphabet(java.lang.String basen)`	Tests a given String to see if it contains only valid characters within the alphabet.
`boolean`	`isStrictDecoding()`	Tests true if decoding behavior is strict.
`protected static boolean`	`isWhiteSpace(byte byteToCheck)`	Deprecated. Use `Character.isWhitespace(int)`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - MIME_CHUNK_SIZE
```
public static final int MIME_CHUNK_SIZE
```
    MIME chunk size per RFC 2045 section 6.8.
    The 76 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
    
    See Also:
    
    RFC 2045 section 6.8, Constant Field Values
  - PEM_CHUNK_SIZE
```
public static final int PEM_CHUNK_SIZE
```
    PEM chunk size per RFC 1421 section 4.3.2.4.
    The 64 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
    
    See Also:
    
    RFC 1421 section 4.3.2.4, Constant Field Values
  - MASK_8BITS
```
protected static final int MASK_8BITS
```
    Mask used to extract 8 bits, used in decoding bytes
    
    See Also:
    
    Constant Field Values
  - PAD_DEFAULT
```
protected static final byte PAD_DEFAULT
```
    Byte used to pad output.
    
    See Also:
    
    Constant Field Values
  - DECODING_POLICY_DEFAULT
```
protected static final CodecPolicy DECODING_POLICY_DEFAULT
```
    The default decoding policy.
    
    Since:
    
    1.15
  - PAD
```
@Deprecated
protected final byte PAD
```
    Deprecated.
    Use pad. Will be removed in 2.0.
    
    Deprecated: Will be removed in 2.0.
    Instance variable just in case it needs to vary later
    
    See Also:
    
    Constant Field Values
  - pad
```
protected final byte pad
```
    Pad byte. Instance variable just in case it needs to vary later.
  - lineLength
```
protected final int lineLength
```
    Chunksize for encoding. Not used when decoding. A value of zero or less implies no chunking of the encoded data. Rounded down to the nearest multiple of encodedBlockSize.
- Constructor Detail
  - BaseNCodec
```
protected BaseNCodec(BaseNCodec.AbstractBuilder<?,?> builder)
```
    Constructs a new instance for a subclass.
    
    Parameters:
    
    builder - How to build this portion of the instance.
    
    Since:
    
    1.20.0
  - BaseNCodec
```
@Deprecated
protected BaseNCodec(int unencodedBlockSize,
                     int encodedBlockSize,
                     int lineLength,
                     int chunkSeparatorLength)
```
    Deprecated.
    Use BaseNCodec(AbstractBuilder).
    
    Constructs a new instance.
    Note lineLength is rounded down to the nearest multiple of the encoded block size. If chunkSeparatorLength is zero, then chunking is disabled.
    
    Parameters:
    
    unencodedBlockSize - the size of an unencoded block (for example Base64 = 3).
    
    encodedBlockSize - the size of an encoded block (for example Base64 = 4).
    
    lineLength - if > 0, use chunking with a length lineLength.
    
    chunkSeparatorLength - the chunk separator length, if relevant.
  - BaseNCodec
```
@Deprecated
protected BaseNCodec(int unencodedBlockSize,
                     int encodedBlockSize,
                     int lineLength,
                     int chunkSeparatorLength,
                     byte pad)
```
    Deprecated.
    Use BaseNCodec(AbstractBuilder).
    
    Constructs a new instance.
    Note lineLength is rounded down to the nearest multiple of the encoded block size. If chunkSeparatorLength is zero, then chunking is disabled.
    
    Parameters:
    
    unencodedBlockSize - the size of an unencoded block (for example Base64 = 3).
    
    encodedBlockSize - the size of an encoded block (for example Base64 = 4).
    
    lineLength - if > 0, use chunking with a length lineLength.
    
    chunkSeparatorLength - the chunk separator length, if relevant.
    
    pad - byte used as padding byte.
  - BaseNCodec
```
@Deprecated
protected BaseNCodec(int unencodedBlockSize,
                     int encodedBlockSize,
                     int lineLength,
                     int chunkSeparatorLength,
                     byte pad,
                     CodecPolicy decodingPolicy)
```
    Deprecated.
    Use BaseNCodec(AbstractBuilder).
    
    Constructs a new instance.
    Note lineLength is rounded down to the nearest multiple of the encoded block size. If chunkSeparatorLength is zero, then chunking is disabled.
    
    Parameters:
    
    unencodedBlockSize - the size of an unencoded block (for example Base64 = 3).
    
    encodedBlockSize - the size of an encoded block (for example Base64 = 4).
    
    lineLength - if > 0, use chunking with a length lineLength.
    
    chunkSeparatorLength - the chunk separator length, if relevant.
    
    pad - byte used as padding byte.
    
    decodingPolicy - Decoding policy.
    
    Since:
    
    1.15
- Method Detail
  - getChunkSeparator
```
public static byte[] getChunkSeparator()
```
    Gets a copy of the chunk separator per RFC 2045 section 2.1.
    
    Returns:
    
    the chunk separator.
    
    Since:
    
    1.15
    
    See Also:
    
    RFC 2045 section 2.1
  - isWhiteSpace
```
@Deprecated
protected static boolean isWhiteSpace(byte byteToCheck)
```
    Deprecated.
    Use Character.isWhitespace(int).
    
    Checks if a byte value is whitespace or not.
    
    Parameters:
    
    byteToCheck - the byte to check.
    
    Returns:
    
    true if byte is whitespace, false otherwise.
    
    See Also:
    
    Character.isWhitespace(int)
  - containsAlphabetOrPad
```
protected boolean containsAlphabetOrPad(byte[] arrayOctet)
```
    Tests a given byte array to see if it contains any characters within the alphabet or PAD. Intended for use in checking line-ending arrays.
    
    Parameters:
    
    arrayOctet - byte array to test.
    
    Returns:
    
    true if any byte is a valid character in the alphabet or PAD; false otherwise.
  - decode
```
public byte[] decode(byte[] array)
```
    Decodes a byte[] containing characters in the Base-N alphabet.
    
    Specified by:
    
    decode in interface BinaryDecoder
    
    Parameters:
    
    array - A byte array containing Base-N character data.
    
    Returns:
    
    a byte array containing binary data.
  - decode
```
public java.lang.Object decode(java.lang.Object obj)
                        throws DecoderException
```
    Decodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[] or String.
    
    Specified by:
    
    decode in interface Decoder
    
    Parameters:
    
    obj - Object to decode.
    
    Returns:
    
    An object (of type byte[]) containing the binary data which corresponds to the byte[] or String supplied.
    
    Throws:
    
    DecoderException - if the parameter supplied is not of type byte[].
  - decode
```
public byte[] decode(java.lang.String array)
```
    Decodes a String containing characters in the Base-N alphabet.
    
    Parameters:
    
    array - A String containing Base-N character data.
    
    Returns:
    
    a byte array containing binary data.
  - encode
```
public byte[] encode(byte[] array)
```
    Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
    
    Specified by:
    
    encode in interface BinaryEncoder
    
    Parameters:
    
    array - a byte array containing binary data.
    
    Returns:
    
    A byte array containing only the base N alphabetic character data.
  - encode
```
public byte[] encode(byte[] array,
                     int offset,
                     int length)
```
    Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
    
    Parameters:
    
    array - a byte array containing binary data.
    
    offset - initial offset of the subarray.
    
    length - length of the subarray.
    
    Returns:
    
    A byte array containing only the base N alphabetic character data.
    
    Since:
    
    1.11
  - encode
```
public java.lang.Object encode(java.lang.Object obj)
                        throws EncoderException
```
    Encodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].
    
    Specified by:
    
    encode in interface Encoder
    
    Parameters:
    
    obj - Object to encode.
    
    Returns:
    
    An object (of type byte[]) containing the Base-N encoded data which corresponds to the byte[] supplied.
    
    Throws:
    
    EncoderException - if the parameter supplied is not of type byte[].
  - encodeAsString
```
public java.lang.String encodeAsString(byte[] array)
```
    Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet. Uses UTF8 encoding.
    This is a duplicate of encodeToString(byte[]); it was merged during refactoring.
    
    Parameters:
    
    array - a byte array containing binary data.
    
    Returns:
    
    String containing only character data in the appropriate alphabet.
    
    Since:
    
    1.5
  - encodeToString
```
public java.lang.String encodeToString(byte[] array)
```
    Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet. Uses UTF8 encoding.
    
    Parameters:
    
    array - a byte array containing binary data.
    
    Returns:
    
    A String containing only Base-N character data.
  - ensureBufferSize
```
protected byte[] ensureBufferSize(int size,
                                  org.apache.commons.codec.binary.BaseNCodec.Context context)
```
    Ensures that the buffer has room for size bytes
    
    Parameters:
    
    size - minimum spare space required.
    
    context - the context to be used.
    
    Returns:
    
    the buffer.
  - getCodecPolicy
```
public CodecPolicy getCodecPolicy()
```
    Gets the decoding behavior policy.
    The default is lenient. If the decoding policy is strict, then decoding will raise an IllegalArgumentException if trailing bits are not part of a valid encoding. Decoding will compose trailing bits into 8-bit bytes and discard the remainder.
    
    Returns:
    
    true if using strict decoding.
    
    Since:
    
    1.15
  - getDefaultBufferSize
```
protected int getDefaultBufferSize()
```
    Gets the default buffer size. Can be overridden.
    
    Returns:
    
    the default buffer size.
  - getEncodedLength
```
public long getEncodedLength(byte[] array)
```
    Gets the amount of space needed to encode the supplied array.
    
    Parameters:
    
    array - byte[] array which will later be encoded.
    
    Returns:
    
    amount of space needed to encode the supplied array. Returns a long since a max-len array will require > Integer.MAX_VALUE.
  - isInAlphabet
```
protected abstract boolean isInAlphabet(byte value)
```
    Tests whether or not the octet is in the current alphabet. Does not allow whitespace or pad.
    
    Parameters:
    
    value - The value to test.
    
    Returns:
    
    true if the value is defined in the current alphabet, false otherwise.
  - isInAlphabet
```
public boolean isInAlphabet(byte[] arrayOctet,
                            boolean allowWSPad)
```
    Tests a given byte array to see if it contains only valid characters within the alphabet. The method optionally treats whitespace and pad as valid.
    
    Parameters:
    
    arrayOctet - byte array to test.
    
    allowWSPad - if true, then whitespace and PAD are also allowed.
    
    Returns:
    
    true if all bytes are valid characters in the alphabet or if the byte array is empty; false, otherwise.
  - isInAlphabet
```
public boolean isInAlphabet(java.lang.String basen)
```
    Tests a given String to see if it contains only valid characters within the alphabet. The method treats whitespace and PAD as valid.
    
    Parameters:
    
    basen - String to test.
    
    Returns:
    
    true if all characters in the String are valid characters in the alphabet or if the String is empty; false, otherwise.
    
    See Also:
    
    isInAlphabet(byte[], boolean)
  - isStrictDecoding
```
public boolean isStrictDecoding()
```
    Tests true if decoding behavior is strict. Decoding will raise an IllegalArgumentException if trailing bits are not part of a valid encoding.
    The default is false for lenient decoding. Decoding will compose trailing bits into 8-bit bytes and discard the remainder.
    
    Returns:
    
    true if using strict decoding.
    
    Since:
    
    1.15

Class BaseNCodec

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MIME_CHUNK_SIZE

PEM_CHUNK_SIZE

MASK_8BITS

PAD_DEFAULT

DECODING_POLICY_DEFAULT

PAD

pad

lineLength

Constructor Detail

BaseNCodec

BaseNCodec

BaseNCodec

BaseNCodec

Method Detail

getChunkSeparator

isWhiteSpace

containsAlphabetOrPad

decode

decode

decode

encode

encode

encode

encodeAsString

encodeToString

ensureBufferSize

getCodecPolicy

getDefaultBufferSize

getEncodedLength

isInAlphabet

isInAlphabet

isInAlphabet

isStrictDecoding